optimization and some cleanup; mostly from kshe (except the unmap() part)

1 files changed, 51 insertions, 67 deletions

diff --git a/src/lib/libc/stdlib/malloc.c b/src/lib/libc/stdlib/malloc.c
index 02349d9ef9..b0083cb91e 100644
--- a/src/lib/libc/stdlib/malloc.c
+++ b/src/lib/libc/stdlib/malloc.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: malloc.c,v 1.238 2018/01/01 12:41:48 otto Exp $       */
+/*      $OpenBSD: malloc.c,v 1.239 2018/01/08 12:20:23 otto Exp $       */
 /*
  * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net>
  * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@@ -376,12 +376,11 @@ omalloc_parseopt(char opt)
         case 'X':
                 mopts.malloc_xmalloc = 1;
                 break;
-        default: {
+        default:
                 dprintf(STDERR_FILENO, "malloc() warning: "
                     "unknown char in MALLOC_OPTIONS\n");
                 break;
         }
-        }
 }
 
 static void
@@ -448,9 +447,6 @@ omalloc_init(void)
                 ;
 }
 
-/*
- * Initialize a dir_info, which should have been cleared by caller
- */
 static void
 omalloc_poolinit(struct dir_info **dp)
 {
@@ -502,7 +498,7 @@ omalloc_grow(struct dir_info *d)
         size_t i;
         struct region_info *p;
 
-        if (d->regions_total > SIZE_MAX / sizeof(struct region_info) / 2 )
+        if (d->regions_total > SIZE_MAX / sizeof(struct region_info) / 2)
                 return 1;
 
         newtotal = d->regions_total * 2;
@@ -641,9 +637,9 @@ static void
 unmap(struct dir_info *d, void *p, size_t sz, int clear)
 {
         size_t psz = sz >> MALLOC_PAGESHIFT;
-        size_t rsz, tounmap;
+        size_t rsz;
         struct region_info *r;
-        u_int i, offset;
+        u_int i, offset, mask;
 
         if (sz != PAGEROUND(sz))
                 wrterror(d, "munmap round");
@@ -662,30 +658,34 @@ unmap(struct dir_info *d, void *p, size_t sz, int clear)
                 STATS_SUB(d->malloc_used, sz);
                 return;
         }
-        tounmap = 0;
-        if (psz > rsz)
-                tounmap = psz - rsz;
         offset = getrbyte(d);
-        for (i = 0; tounmap > 0 && i < mopts.malloc_cache; i++) {
-                r = &d->free_regions[(i + offset) & (mopts.malloc_cache - 1)];
-                if (r->p != NULL) {
-                        rsz = r->size << MALLOC_PAGESHIFT;
-                        if (munmap(r->p, rsz))
-                                wrterror(d, "munmap %p", r->p);
-                        r->p = NULL;
-                        if (tounmap > r->size)
-                                tounmap -= r->size;
-                        else
-                                tounmap = 0;
-                        d->free_regions_size -= r->size;
-                        r->size = 0;
-                        STATS_SUB(d->malloc_used, rsz);
+        mask = mopts.malloc_cache - 1;
+        if (psz > rsz) {
+                size_t tounmap = psz - rsz;
+                i = 0;
+                for (;;) {
+                        r = &d->free_regions[(i + offset) & mask];
+                        if (r->p != NULL) {
+                                rsz = r->size << MALLOC_PAGESHIFT;
+                                if (munmap(r->p, rsz))
+                                        wrterror(d, "munmap %p", r->p);
+                                r->p = NULL;
+                                if (tounmap > r->size)
+                                        tounmap -= r->size;
+                                else
+                                        tounmap = 0;
+                                d->free_regions_size -= r->size;
+                                STATS_SUB(d->malloc_used, rsz);
+                                if (tounmap == 0) {
+                                        offset = i;
+                                        break;
+                                }
+                        }
+                        i++;
                 }
         }
-        if (tounmap > 0)
-                wrterror(d, "malloc cache underflow");
-        for (i = 0; i < mopts.malloc_cache; i++) {
-                r = &d->free_regions[(i + offset) & (mopts.malloc_cache - 1)];
+        for (i = 0; ; i++) {
+                r = &d->free_regions[(i + offset) & mask];
                 if (r->p == NULL) {
                         if (clear)
                                 memset(p, 0, sz - mopts.malloc_guard);
@@ -702,8 +702,6 @@ unmap(struct dir_info *d, void *p, size_t sz, int clear)
                         break;
                 }
         }
-        if (i == mopts.malloc_cache)
-                wrterror(d, "malloc free slot lost");
         if (d->free_regions_size > mopts.malloc_cache)
                 wrterror(d, "malloc cache overflow");
 }
@@ -723,7 +721,6 @@ zapcacheregion(struct dir_info *d, void *p, size_t len)
                                 wrterror(d, "munmap %p", r->p);
                         r->p = NULL;
                         d->free_regions_size -= r->size;
-                        r->size = 0;
                         STATS_SUB(d->malloc_used, rsz);
                 }
         }
@@ -760,7 +757,6 @@ map(struct dir_info *d, void *hint, size_t sz, int zero_fill)
                         if (r->size == psz) {
                                 p = r->p;
                                 r->p = NULL;
-                                r->size = 0;
                                 d->free_regions_size -= psz;
                                 if (mopts.malloc_freeunmap)
                                         mprotect(p, sz, PROT_READ | PROT_WRITE);
@@ -808,10 +804,7 @@ init_chunk_info(struct dir_info *d, struct chunk_info *p, int bits)
         int i;
 
         if (bits == 0) {
-                p->shift = 1;
-                i = MALLOC_MINSIZE - 1;
-                while (i >>= 1)
-                        p->shift++;
+                p->shift = MALLOC_MINSHIFT;
                 p->total = p->free = MALLOC_PAGESIZE >> p->shift;
                 p->size = 0;
                 p->offset = 0xdead;
@@ -824,13 +817,9 @@ init_chunk_info(struct dir_info *d, struct chunk_info *p, int bits)
         p->canary = (u_short)d->canary1;
 
         /* set all valid bits in the bitmap */
-        for (i = 0; p->total - i >= MALLOC_BITS; i += MALLOC_BITS)
-                p->bits[i / MALLOC_BITS] = (u_short)~0U;
-
-        if (i < p->total)
-                p->bits[i / MALLOC_BITS] = 0;
-        for (; i < p->total; i++)
-                p->bits[i / MALLOC_BITS] |= (u_short)1U << (i % MALLOC_BITS);
+        i = p->total - 1;       
+        memset(p->bits, 0xff, sizeof(p->bits[0]) * (i / MALLOC_BITS));
+        p->bits[i / MALLOC_BITS] = (2U << (i % MALLOC_BITS)) - 1;
 }
 
 static struct chunk_info *
@@ -907,23 +896,20 @@ err:
 static int
 find_chunksize(size_t size)
 {
-        int             i, j;
+        int r;
 
-        /* Don't bother with anything less than this */
-        /* unless we have a malloc(0) requests */
-        if (size != 0 && size < MALLOC_MINSIZE)
+        /* malloc(0) is special */
+        if (size == 0)
+                return 0;
+
+        if (size < MALLOC_MINSIZE)
                 size = MALLOC_MINSIZE;
+        size--;
 
-        /* Find the right bucket */
-        if (size == 0)
-                j = 0;
-        else {
-                j = MALLOC_MINSHIFT;
-                i = (size - 1) >> (MALLOC_MINSHIFT - 1);
-                while (i >>= 1)
-                        j++;
-        }
-        return j;
+        r = MALLOC_MINSHIFT;
+        while (size >> r)
+                r++;
+        return r;
 }
 
 static void
@@ -1013,7 +999,7 @@ found:
         *lp ^= u;
 
         /* If there are no more free, remove from free-list */
-        if (!--bp->free)
+        if (--bp->free == 0)
                 LIST_REMOVE(bp, entries);
 
         /* Adjust to the real offset of that chunk */
@@ -1048,8 +1034,8 @@ validate_canary(struct dir_info *d, u_char *ptr, size_t sz, size_t allocated)
         while (p < q) {
                 if (*p != SOME_JUNK) {
                         wrterror(d, "chunk canary corrupted %p %#tx@%#zx%s",
-                            ptr, p - ptr, sz, *p == SOME_FREEJUNK ?
-                                " (double free?)" : "");
+                            ptr, p - ptr, sz,
+                            *p == SOME_FREEJUNK ? " (double free?)" : "");
                 }
                 p++;
         }
@@ -1173,8 +1159,7 @@ omalloc(struct dir_info *pool, size_t sz, int zero_fill, void *f)
                                 else
                                         memset(p, SOME_JUNK,
                                             psz - mopts.malloc_guard);
-                        }
-                        else if (mopts.chunk_canaries)
+                        } else if (mopts.chunk_canaries)
                                 fill_canary(p, sz - mopts.malloc_guard,
                                     psz - mopts.malloc_guard);
                 }
@@ -1225,7 +1210,7 @@ _malloc_init(int from_rthreads)
         max = from_rthreads ? _MALLOC_MUTEXES : 1;
         if (((uintptr_t)&malloc_readonly & MALLOC_PAGEMASK) == 0)
                 mprotect(&malloc_readonly, sizeof(malloc_readonly),
-                     PROT_READ | PROT_WRITE);
+                    PROT_READ | PROT_WRITE);
         for (i = 0; i < max; i++) {
                 if (mopts.malloc_pool[i])
                         continue;
@@ -2030,8 +2015,7 @@ omemalign(struct dir_info *pool, size_t alignment, size_t sz, int zero_fill,
                             SOME_JUNK, psz - sz);
                 else
                         memset(p, SOME_JUNK, psz - mopts.malloc_guard);
-        }
-        else if (mopts.chunk_canaries)
+        } else if (mopts.chunk_canaries)
                 fill_canary(p, sz - mopts.malloc_guard,
                     psz - mopts.malloc_guard);